Textured hexagonal boron nitride (h-BN) matrix composite ceramics were prepared by hot- pressing using different contents of 3Y₂O₃-5Al₂O₃ (molar ratio of 3:5) as the sintering additive. During hot-pressing, the liquid Y₃Al₅O₁₂ (YAG) phase showing good wettability to h-BN grains was in situ formed through the reaction between Y₂O₃ and Al₂O₃, and a coherent relationship between h-BN and YAG was observed with [010]_h-BN// $[\overline{1}11]$_YAG and (002)_h-BN//(321)_YAG. In the YAG liquid phase environment formed during hot-pressing, plate-like h-BN grains were rotated under the uniaxial sintering pressure and preferentially oriented with their basal surfaces perpendicular to the sintering pressure direction, forming textured microstructures with the c-axis of h-BN grains oriented parallel to the sintering pressure direction, which give these composite ceramics anisotropy in their mechanical and thermal properties. The highest texture degree was found in the specimen with 30 wt% YAG, which also possesses the highest anisotropy degree in thermal conductivity. The aggregation of YAG phase was observed in the specimen with 40 wt% YAG, which resulted in the buckling of h-BN plates and significantly reduced the texture degree.

Ceramics are usually composed of randomly oriented grains and intergranular phases, so their properties are the statistical average along each direction and show isotropy corresponding to the uniform microstructures. Some methods have been developed to achieve directional grain arrangement and preferred orientation growth during ceramic preparation, and then textured ceramics with anisotropic properties are obtained. Texture microstructures give particular properties to ceramics along specific directions, which can effectively expand their application fields. In this review, typical texturing techniques suitable for ceramic materials, such as hot working, magnetic alignment, and templated grain growth (TGG), are discussed. Several typical textured structural ceramics including α-Al₂O₃ and related nacre bioinspired ceramics, Si₃N₄ and SiAlON, h-BN, MB₂ matrix ultra-high temperature ceramics, MAX phases and their anisotropic properties are presented.